Powder metallurgy process for producing parts having high strength and hardness from Si-Mn or Si-Mn-C alloyed steel

摘要

The invention relates to a method for the powder-metallurgical production of moldings of high strength and hardness from silicon-manganese or silicon-manganese-carbon alloyed steels. The previously known manufacturing processes for such steels have not brought the hoped-for results. The invention is intended to provide a method for the powder-metallurgical production of molded parts of high strength and hardness as well as sufficient toughness from sintered steels, in which only easily available alloy elements, the purchase of which is ensured in the long term, are used. The shaped parts are said to be able to be manufactured to size by the invention during the sintering process, i.e. they should not suffer any shrinkage and / or no loss of strength due to anti-shrinkage measures due to the addition of alloying elements. This is achieved in that the alloy elements Si and Mn or Si, Mn and C are made of ferrosilicon, ferromanganese or a silicon-manganese-iron master alloy with silicon and manganese contents in the ranges of 10 to 30% by weight. Si, 20 to 70% by weight Mn, remainder Fe and graphite in powder form are mixed with an iron powder and the powder mixture is pressed in a manner known per se and sintered and cooled at a temperature in the range from 1150 ° C. to 1250 ° C. under an inert gas atmosphere .